The machine is engaged and rotates around the form, creating a layer of material between 1 1/2 and 2 inches (38 and 51 mm) thickness. Simultaneously, each layer is deaerated at a rate of 600-700 strokes per revolution using dual forks. The fork tines penetrate to a depth of approximately 4 1/2 inches (114 mm), thus each layer is penetrated at least twice, effectively mixing the layers and providing optimum pre-compaction. The hopper is refilled as necessary and the process repeated until the top of the form is reached. The RIS can be adjusted to line various size furnaces having different dimensions. Conventional, manual installation is both labour intensive and dangerous, particularly with respect to silica dust. In addition, consistency is difficult to achieve with both layering of material and uninterrupted deaeration..